BACKGROUND CONTEXT: For chronic low back pain, the causal mechanisms between pathological features from imaging and patient symptoms are unclear. For instance, disc herniations can often be present without symptoms. There remains a need for improved knowledge of the pathophysiological mechanisms that explore spinal tissue damage and clinical manifestations of pain and disability. Spaceflight and astronaut health provides a rare opportunity to study potential low back pain mechanisms longitudinally. Spaceflight disrupts diurnal loading on the spine and several lines of evidence indicate that astronauts are at a heightened risk for low back pain and disc herniation following spaceflight. PURPOSE: To examine the relationship between prolonged exposure to microgravity and the elevated incidence of postflight disc herniation, we conducted a longitudinal study to track the spinal health of twelve NASA astronauts before and after approximately 6-months in space. We hypothesize that the incidence of postflight disc herniation and low back complaints associates with spaceflight-included muscle atrophy and pre-existing spinal pathology. STUDY DESIGN: This is a prospective longitudinal study. PATIENT SAMPLE: Our sample included a cohort of twelve astronaut crewmembers. OUTCOME MEASURES: From 3T MRI, we quantified disc water content (ms), disc degeneration (Pfirrmann grade), vertebral end plate irregularities, facet arthropathy and/ fluid, high intensity zones, disc herniation, multifidus total cross-sectional area (cm 2 ), multifidus lean muscle cross-sectional area (cm 2 ), and muscle quality/composition (%). From quantitative fluoroscopy we quantified, maximum flexion-extension ROM (˚), maximum lateral bending ROM (˚), and maximum translation (%). Lastly, patient outcomes and clinical notes were used for identifying postflight symptoms associated with disc herniations from 3T MRI. METHODS: Advanced imaging data from 3T MRI were collected at three separate time points in relation to spending 6-months in space: (1) within a year before launch ("pre-flight"), (2) within a FDA device/drug status: Not applicable.

Background: Patients with limited health literacy require online educational materials to be written below a sixth grade level for optimal understanding. We assessed the quality, accuracy, and readability of online materials for Kienböck disease (KD). Methods: “Kienbock’s Disease” and “Lunate Avacular Necrosis” were entered into 3 search engines. The first 25 Web sites from each search were collected. Quality was assessed via a custom grading rubric, accuracy by 2 residents and a fellow, and readability by Flesch-Kincaid grade level (FKGL) and New Dale-Chall test. Web sites were stratified according to the search term, FKGL, order of appearance, and authorship type. Results: A total of 38 unique Web sites were included, of which 22 were assigned to “KD” and 16 to “Lunate Avascular Necrosis.” The average quality score out of 30, accuracy score out of 12, and FKGL for all Web sites were 13.3 ± 7.3, 10.4 ± 1.9, and 10.5 ± 1.4, respectively. Web sites assigned to the term “Kienbock’s Disease” had a significantly higher FKGL. Web sites of higher FKGL had significantly worse accuracy scores. Order of appearance had no influence. Physician specialty societies (PSS) had a significantly lower FKGL than Web sites of other authorship types. Conclusions: Despite concerted efforts by national organizations, the readability of online patient materials is above the recommended level for KD. Patients with limited health literacy will be most affected by this reality. Until readability improves, patients should continue to consult their physicians when uncertain and prioritize Web sites that are easier to read and produced by PSS.

Purpose Fat infiltration (FI) of the paraspinal muscles (PSMs) measured using MRI is an aspect of muscle quality and is considered to be worse in chronic low back pain (cLBP) patients. However, there is not a clear association between paraspinal muscle FI and cLBP, leaving the clinical importance of paraspinal muscle composition unestablished. The spatial distribution of FI in the PSMs may inform mechanistic understanding of non-specific cLBP as it relates to degenerative intervertebral disc (IVD) pathology. We hypothesized that paraspinal muscle fat-mapping would reveal distinct FI distribution patterns in relation to cLBP symptoms and proximity to symptomatic IVD degeneration. Methods From advanced-sequence water-fat MRI of 40 axial cLBP patients and 21 controls, we examined the spatial distribution of paraspinal muscle FI in relation to the center of rotation at the L4L5 disc. Using statistical parametric mapping, we compared FI patterns for multifidus (MF), erector spinae (ES), and psoas between patients and controls, and to the presence and severity of adjacent degenerative IVD pathology. Results The spatial distribution of PSMs FI differs between PSMs and according to symptoms and the adjacent degenerative IVD pathology. Furthermore, the region of MF closest to the disc center of rotation appears most susceptible to FI in the presence of symptomatic IVD degeneration. Conclusion Our study identified spatial distribution patterns of FI in the PSMs as a potential diagnostic biomarker that may also provide granular mechanistic insights into spine biomechanics related to cLBP, as well as advancing the use of prior summary measures limited to overall muscle FI.

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